The present invention relates to the interlocking of stacked cargo containers and, more particularly, to automatic locks which are secured to and travel with the container.
The prior art includes various devices for interconnecting stacked cargo containers. These devices include manual locks, semi-automatic locks, and automatic locks. As will be recognized to those skilled in the art, manual locking devices must be manually installed within the corner fitting, are manually locked, are manually unlocked, and are then manually removed from the corner fitting. Semi-automatic devices must be manually installed in the corner fitting, provide automatic locking but must be manually unlocked, and are then manually removed from the corner fitting. Finally, automatic devices must be manually installed in the corner fitting, provide automatically locking and unlocking, and are then manually removed from the corner fitting.
Although the art has advanced from manual locks to semi-automatic locks to automatic locks, and although each new design has provided certain additional benefits, today's fully automatic locks still have certain drawbacks. First, many prior art automatic locks still require an operator to manually install and remove the device from the corner fitting of the container, resulting in additional time and cost during loading/unloading. Second, many prior art automatic devices are designed to release once a predetermined friction force is overcome during hoisting of the container. Due to such factors as tolerances, wear and abuse of the corner fittings, designs which rely upon release of friction forces can provide inconsistent results.
There is therefore a need in the art for an automatic lock which is capable of interconnecting two stacked containers, and of locking and unlocking without being adversely affected by factors such as tolerances, wear and abuse of the corner fittings, even when relying upon the overcoming of a friction force to release the device. The same automatic lock is preferably affixed to the container, thereby eliminating the need to install and remove such device during loading/unloading of the container.